I'm not sure you really need to bother with a microcontroller... couldn't you do the job with a 555 timer and some counter ICs? If you really want to use an arduino for this simple task, look up the millis() function and how it relates to keeping time.

I need this code here, But only for the light, Could you edit it for me in a way that only the light will work? And I just want to use flower mode. http://www.instructables.com/files/orig/FY8/6LS8/FV4LSLHL/FY86LS8FV4LSLHL.tmp thanks, And if you do good you may get a donation

/* Blink Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain. */

// Pin 13 has an LED connected on most Arduino boards.// give it a name:int led = 13;

// the setup routine runs once when you press reset:void setup() { // initialize the digital pin as an output. pinMode(led, OUTPUT); }

// the loop routine runs over and over again forever:void loop() { digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level) delay(43200000); // wait for 12 hours digitalWrite(led, LOW); // turn the LED off by making the voltage LOW delay(43200000); // wait for 12 hours}

This is a modied version of the very first arduino project, blink. it originally blinks an LED on pin 13. The only thing I did to change this program was to change the timing from 1 second, to 12 hours.

My guess is that you will need more than 40ma, so you will need to use transistors or relays to switch to higher current devices, but the code is still the same.

Honestly, i think the cheapo 24 hour switch thing like someone previously mentioned would be more appropriate.

Like the previous code example, this would only do the flowering lights, which is really all you need, the other room would be lighted 24/7, and not need anything to control that.

I would be interested to find out how well LEDs work for growing. Most setups that i have seen require their own service panel, lots of expensive lights that use crazy amounts of current, and enclosures with fans to keep the lights from heating everything too much.